e58863238e
Per review on #1715: theme color values may be a 256-color palette index (colorValueSchema = string | number), so a custom theme can set a light statusLineBg numerically (e.g. 15 = white). bgIsLight only handled hex strings and returned false for numbers, routing those light themes through the dark-accent path and reintroducing the unreadable accent. Add paletteLuminance (0-15 xterm defaults, 16-231 color cube, 232-255 grayscale) and a colorLuminance(string|number) dispatcher; route bgIsLight and isLightTheme through it. Tests added.